Summary: Opioid abuse is a major epidemic in the United States. In 2017 alone, abuse of prescription and illicit opioids resulted in over 60,000 deaths. The transition from therapeutic use of opioid pain relievers to destructive substance abuse occurs, in part, through maladaptive activation of mesocorticolimbic brain circuits. How these various sensory, reward, and stress neural circuits act at the systems, cellular and molecular levels remain poorly understood. As we work to advance our understanding of the development of opioid use disorder, we need to develop fundamental insights into how opioid circuits function in reward and aversion. In addition, we need to learn how these circuits are modulated, altered, and adapted over time in animal models of opioid addiction. We aim to leverage the diverse team of investigators at UW towards answering these questions. We propose to establish an advanced Imaging and Addiction Neural Circuits Core (INCC) to provide UW addiction researchers, neuroscientists, and the wider community with a suite of advanced neurotechnologies, for in vivo neural circuit perturbation and analysis. Beyond building and continually renewing a state-of-the-art imaging facility, a principal role of the Core will be to train the NIDA P30 Investigators in its uses in order to enhance the research of their NIDA funded projects. We will also disseminate these tools to the larger research community by providing on-site training. Collectivity, these resources will enable researchers at UW and beyond to identify and correct neurocircuit maladaptation observed in opioid addiction models.